Olmesartan-associated gastroduodenitis that was detected on endoscopic follow-up

We present a rare case of olmesartan-associated gastroduodenitis in a 65-year-old female with predominant upper gastrointestinal symptoms and significant changes in endoscopic findings over a short period. The patient presented with epigastralgia and nausea but no diarrhea. Esophagogastroduodenoscopy (EGD) performed 26 months earlier showed a duodenal ulcer and partial mucosal atrophy in the lower gastric body. EGD conducted at our hospital revealed diffuse atrophic mucosa throughout the stomach and fragile mucosa from the middle gastric body to the antrum, with white purulent adhesions. Diffuse inflammatory changes were also observed in the duodenal bulb and descending part. Mucosal biopsy showed atrophic changes, inflammatory cell infiltrations, and epithelial detachments in both the stomach and duodenum. Colonoscopy findings were normal. After discontinuing olmesartan, the patient's symptoms improved immediately. A follow-up EGD conducted 4 months after discontinuation revealed marked improvement in the stomach and duodenum. At 16 months post-discontinuation, the patient remained asymptomatic, with minimal inflammation and residual gastric atrophy observed on EGD. This case underscores the importance of considering olmesartan as a potential cause of gastroduodenitis, particularly when symptoms and endoscopic findings improve after discontinuation of the medication.